Conventionally, in a case where a printing medium that printing is performed on its one side and a printing medium that printing is performed on its both sides are continuously output, it has been known to use a printing apparatus to which a controlling method of outputting these media by switching between a single-sided conveying route for single-sided printing and a double-sided conveying route for double-sided printing is applied.
On the other hand, it has been also known to use a printing apparatus to which a controlling method of outputting the printing medium that the printing is performed on its one side and the printing medium that the printing is performed on its both sides through an identical conveying route is applied (for example, see PTL 1).
In each of the printing apparatuses constituted as described above, there are following problems when a single-sided page that an image has been formed on its one side and a double-sided page that images have been formed respectively on its both sides are continuously output. That is, superiority or inferiority between an output time for outputting the single-sided pages and the double-sided pages by properly switching between the single-sided conveying route and the double-sided conveying route and an output time for outputting the single-sided pages and the double-sided pages through only the double-sided conveying route depends on a combination of the single-sided pages and the double-sided pages in a job to be output and a characteristic of the apparatus itself.
Therefore, it is not easy for an operator of the printing apparatus to select, from the above two controlling methods, the one controlling method by which the output time is shorter in regard to the job in which the single-sided pages and the double-sided pages are complicatedly combined with others.
Moreover, it is impossible in the background art to perform the printing while switching between the above two controlling methods in regard to fragmentary page groups included in the job. Therefore, when tendencies of combinations of the single-sided pages and the double-sided pages are fragmentarily different, output speed partially slows down.